Weight Loss Injections

Q: Can you get weight loss medications on the NHS?

In some cases, yes. Certain weight loss injections may be available on the NHS, but only if you meet strict eligibility criteria. This usually includes having obesity (a BMI above a set threshold) and having health conditions linked to excess weight, such as type 2 diabetes or high blood pressure. Access can vary depending on where you live, and waiting lists are common. Many people choose private providers for quicker access and ongoing support.

Q: Do weight loss injections work?

Yes, clinical trials show that weight loss injections can be highly effective when combined with healthy lifestyle changes. On average, people lose significantly more weight with these medicines than through lifestyle changes alone. Some achieve a reduction of 10–20% of their body weight over 12–18 months. Results vary depending on the medication used, how long treatment is continued, and how well lifestyle changes are followed alongside.

Q: What is the difference between weight loss injections and pills?

The way a treatment is given, whether as an injection or a pill, doesn’t necessarily mean it works differently. What really matters is the active ingredient. At the moment, all approved weight loss injections work by mimicking natural gut hormones that help regulate appetite and blood sugar, and they’re usually taken once a week. Weight loss pills, on the other hand, can work in different ways. Some act like the injections by targeting appetite signals, while others such as Orlistat reduce the amount of fat your body absorbs from food. These tablets are typically taken every day.

What are weight loss injections?

Weight loss injections are clinically proven medications designed to support people with obesity in losing weight alongside diet and exercise. Unlike fad diets or quick fixes, these treatments are prescribed to individuals who meet specific clinical criteria and are administered as a once weekly injection. They work by mimicking hormones that regulate appetite and food intake, helping people feel fuller for longer and therefore result in reduced calorie consumption.

How do weight loss injections work?

Weight loss injections work by supporting the body’s natural systems that control hunger. They act on two important hormone signals in the gut and brain, helping you feel more in control of your eating habits.

GLP-1 receptors: These tell your brain when you’ve had enough to eat, slow down how quickly food leaves your stomach, and help keep blood sugar steady.¹
GIP receptors: These work alongside GLP-1 to further reduce appetite and improve how your body responds to food.²

Together, these effects mean you feel full sooner, stay full for longer, and have fewer cravings.

How effective are weight loss injections?

Research shows that weight loss injections, when combined with healthy lifestyle changes, can lead to significant results. In large clinical trials, people using these treatments lost on average 15% to 22% of their body weight over 68 to 72 weeks.^1,2 By comparison, those relying on lifestyle changes alone typically lost only a fraction of that. Staying on treatment and making sustainable changes to diet and activity can make these results both achievable and long lasting. The key is consistency.

Weight loss injections: side effects

The most common side effects are usually gastrointestinal, such as nausea, diarrhoea or constipation, cramps, or bloating. These usually improve as your body gets used to the treatment.

Which weight loss injections are available?

There are two weight loss injections currently licensed for the treatment of obesity in the UK.

Tirzepetide (Mounjaro)

Tirzepatide (Mounjaro) is an injection prescribed by clinicians to help with weight management in adults living with obesity. It works by acting on natural gut hormones that play a role in appetite and blood sugar control, helping you feel fuller for longer.²

Large clinical studies have shown that people using tirzepatide lost a significant amount of weight over 72 weeks, with many achieving 20% or more of their body weight compared to just a small change in those not on treatment.² In the UK, it was approved for weight management in November 2023 by the MHRA, and it was later introduced to market in February 2024.

Semaglutide (Wegovy)

Semaglutide is a clinician-prescribed injection used to help adults who are overweight or have obesity who meet medical criteria. It works by mimicking a natural gut hormone that signals when you’re full, slows how quickly food leaves your stomach, and helps keep blood sugar more stable, essentially helping you feel satisfied with smaller portions.¹

Clinical trials have shown it can lead to significant and sustained weight loss, typically around 15% of body weight over 68 weeks, when combined with healthy lifestyle changes.¹ In the UK, semaglutide became available for long-term weight management in 2023.

The difference between Mounjaro and Wegovy

Both Wegovy and Mounjaro work in similar ways, albeit through slightly different mechanisms. Below is a table highlighting these key differences.

Feature	Mounjaro	Wegovy
Active ingredient	Tirzepatide	Semaglutide
Hormones targeted	Activates GLP-1 and GIP receptors (dual action)	Activates GLP-1 receptor only
Condition treated	Obesity	Obesity and reduced cardiovascular risk
Achievable weight loss, according to research	Up to 22.5%²	Up to 17.5%¹
Frequency of injection	Once weekly	Once weekly

Are weight loss injections safe?

Weight loss injections have been approved for use in the UK by the MHRA. When taken under the supervision of a medical professional they are a safe way to lose weight for the vast majority of patients.

Like all medicines, weight loss injections come with some side effects that if not managed properly can cause issues. This is why is it important to only take these medicines under the supervision of a medical professional.

Before being prescribed weight loss injections, patients must undergo a consultation to review their medical history and confirm eligibility. Certain conditions, life stages like pregnancy, and specific medications may conflict with these injections, making them unsuitable for everyone.

FAQS

Your questions answered

Can you get weight loss medications on the NHS?

Do weight loss injections work?

What is the difference between weight loss injections and pills?

KNOWLEDGE

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Glucagon-like peptide-1 (GLP-1) receptor agonists are a type of medication recently approved for the treatment of weight loss.1 Though initially licensed for reducing blood sugar in individuals with type-2 diabetes, they also have the added benefits of slowing gastric emptying, reducing appetite, and aiding in weight loss, all of which contribute to better metabolic health

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References

^{1. Rubino D, Abrahamsson N, Davies M, Hesse D, Greenway FL, Jensen C, et al. Effect of continued weekly subcutaneous semaglutide vs placebo on weight loss maintenance in adults with overweight or obesity: The STEP 4 randomized clinical trial: The STEP 4 randomized clinical trial. JAMA: the journal of the American Medical Association. 2021;325(14): 1414–1425.}

^{2. Ard J, Lee CJ, Gudzune K, Addison B, Lingvay I, Cao D, et al. Weight reduction over time in tirzepatide-treated participants by early weight loss response: Post hoc analysis in SURMOUNT-1. Diabetes, obesity & metabolism. 2025;27(9): 5064–5071.}

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Weight Loss Injections

What are weight loss injections?

How do weight loss injections work?

How effective are weight loss injections?

Weight loss injections: side effects

Tirzepetide (Mounjaro)

Semaglutide (Wegovy)

The difference between Mounjaro and Wegovy

Are weight loss injections safe?

FAQS

KNOWLEDGE

Learn more about our weight loss treatments

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References

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